[Intel-wired-lan] [PATCH net v1] e100: fix device suspend/resume

[Jesse Brandeburg]

As reported in [1], e100 was no longer working for suspend/resume
cycles. The previous commit mentioned in the fixes appears to have
broken things and this attempts to practice best known methods for
device power management and keep wake-up working while allowing
suspend/resume to work. To do this, I reorder a little bit of code
and fix the resume path to make sure the device is enabled.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=214933

Reported-by: Alexey Kuznetsov <axet at me.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg at intel.com>
--
NOTE: Alexey tested it already and it unbreaks his system, which is a
great start. I would like our internal team to try to do some basic
testing but given the age of this part, it shouldn't hold up the patch
going upstream.
---
 drivers/net/ethernet/intel/e100.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c
index 09ae1939e6db..36d52246bdc6 100644
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -3003,9 +3003,10 @@ static void __e100_shutdown(struct pci_dev *pdev, bool *enable_wake)
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct nic *nic = netdev_priv(netdev);
 
+	netif_device_detach(netdev);
+
 	if (netif_running(netdev))
 		e100_down(nic);
-	netif_device_detach(netdev);
 
 	if ((nic->flags & wol_magic) | e100_asf(nic)) {
 		/* enable reverse auto-negotiation */
@@ -3022,7 +3023,7 @@ static void __e100_shutdown(struct pci_dev *pdev, bool *enable_wake)
 		*enable_wake = false;
 	}
 
-	pci_clear_master(pdev);
+	pci_disable_device(pdev);
 }
 
 static int __e100_power_off(struct pci_dev *pdev, bool wake)
@@ -3042,8 +3043,6 @@ static int __maybe_unused e100_suspend(struct device *dev_d)
 
 	__e100_shutdown(to_pci_dev(dev_d), &wake);
 
-	device_wakeup_disable(dev_d);
-
 	return 0;
 }
 
@@ -3051,6 +3050,14 @@ static int __maybe_unused e100_resume(struct device *dev_d)
 {
 	struct net_device *netdev = dev_get_drvdata(dev_d);
 	struct nic *nic = netdev_priv(netdev);
+	int err;
+
+	err = pci_enable_device(to_pci_dev(dev_d));
+	if (err) {
+		netdev_err(netdev, "Resume cannot enable PCI device, aborting\n");
+		return err;
+	}
+	pci_set_master(to_pci_dev(dev_d));
 
 	/* disable reverse auto-negotiation */
 	if (nic->phy == phy_82552_v) {
@@ -3062,10 +3069,11 @@ static int __maybe_unused e100_resume(struct device *dev_d)
 		           smartspeed & ~(E100_82552_REV_ANEG));
 	}
 
-	netif_device_attach(netdev);
 	if (netif_running(netdev))
 		e100_up(nic);
 
+	netif_device_attach(netdev);
+
 	return 0;
 }
 
-- 
2.33.1